Errors/Exceptions

Upon failure, an E_WARNING is emitted.

Notes

Note:

The atime of a file is supposed to change whenever the data blocks of a
file are being read. This can be costly performance-wise when an
application regularly accesses a very large number of files or
directories.

Some Unix filesystems can be mounted with atime updates disabled to
increase the performance of such applications; USENET news spools are a
common example. On such filesystems this function will be useless.

Note:

Note that time resolution may differ
from one file system to another.

Note: The results of this
function are cached. See clearstatcache() for
more details.